Phase Technology CS-6 IW In Wall SpeakerPhaseTech CS 6 Ceiling Speaker The perfect complement to CS in ceiling speakers, the CS 6 iW brings the same high performance and features usually found in much more expensive speakers. value as the rest of the CS line to an in wall design. With a 12 dB oct crossover metal binding posts, high powered . 75 inch variable axis tweeter and a 6. 5 inch Poly woofer, the CS 6 iW is the easy answer for high quality in wall audio at an entry level price.